Contact-less initiation of light emission from photo lamps synchronized with camera operation

ABSTRACT

A magnetically sensitive semiconductor having a plurality of individual magnetically sensitive areas is used to trigger a photoflash lamp in synchronization with shutter operation. A magnetic field is impressed on the individual magnetic areas in time sequense. One is selectively connected to trigger the lamp to provide a selectible time delay for flash operation.

United St tes Patent 1191 Harnden, Jr.

' [111 3,774,511 451 Nov. 27, 1973 CONTACT-LESS lNITlA'lIONOF LIGHTEMISSION FROM PHOTO LAMPS SYNCHRONIZED WITHCAMERA 'r OPERATION 75lnventorz John D. l-larnden, Jr., Schenectady,

NY. I

[73] Assignee: General Electric Company,

Schenectady-,NY.

22 Filed: 0a. 27, 1969 21 Appl.No.: 869 ,800

52.] U.s.c1..... ..95/11.s11

3,106,080 lO/l963 To az... .Q 95 10 CT 3,220,326 11 1965 Scudder 95 10CT 3,518,487 6/l970 Tanaka'etal. 315/228 2,161,355 5/1939" Jacobson..95/11.5 2,336,633 12 1943 Parson,.lr. 95 115 ux 2,382,981 8/1945Edgertom; 95 115 2,486,010 10 1949 Edgerton ..95 11.5 ux 3,211,06910/1965 Rixton; ..95 11.5,

- OTHER PUBLICATIONS 1' Hall EffectPut in lC,'Robert Cushman, Edn, N0-vember II, 1968, pp. 87-93.

Primary Examiner-Samuel S. Matthews Assistant Exdminer-Michael L,Gellner Attorney-Frank L. Neuhause'r, Oscar B. Waddell, .Ioseph B.Forman, NormanC. Fulmer and Henry P.

- Truesd'ell v 57 7 ABSTRACT A magnetically sensitive semiconductorhaving a plurality of individual magnetically sensitive areas is used totrigger a photoflash lamp in synchronization with shutter operation. Amagnetic field is impressed on the individual magnetic areas in timesequense.0ne is selectively connected to triggerthe lamp to provide aselectible time delay for flash operation.

' 1 CONTACT-LESS INITIATION OF LIGHT EMISSIONFROM PHOTO LAMPSSYNCHRONIZED "WITH CAMERA OPERATION This'invention relates to a new andimproved family of contactless light emission initiation circuits foruse in controllingoperation of photolamps employed in The introductionofthe more complex shutter and variable aperturecontrolj mechanisms incameras has required theuse of miniaturized electric motors in thecameras to operate such mechanisms. Thisin turn places a demand onthe'sources of electric energy (such asbatteries) to supply theincreased current necessary to operate such motors. In order to meetthis -requirement, and also-maintain-the. size of the battery Inpracticing the invention, a contact-less photo lamp lightemissioninitiation circuit is providedwhich com prises electric supplyterminal means for connection to asource of electric energy andto photolamp means to initiate light emission fromthe photo lamp means upon theestablishment of a closed electric current path throughthe-electricsupply terminal means, a source of I electric energy and the photo lampmeans to be energized. Contact-less photo lamp light emission initiationmeans are connected in the current path intermediate the photo lampmeans and a source of electric energy for controlling the closure of thecurrent pathjto the photo lamp means whereby electrical resistance offilms normally built up on conventional switch contacts and vibration,bounce, and chatter due to contact impact are. minimized to therebyassure proper energiza: tion of the photo lamp means. The circuitiscompleted by means for synchronizing the initiation of light emissionfrom the'photo lamp means with the passage of power source withinprescribedlimits for use in hand-;

held cameras, it has proven' necessary to reduce the operating voltageof the energy source'to quite lowvalues on the'order of 1 5 volts. Thislow voltagerequire-' ment is further dictated by the desire to fabricatethe control circuits used in such systems'in mincrominiaturizedintegrated circuit form since such integrated circuits 'generally arerequired to beoperated at low voltages. r I

Because of ,the, low voltage requirement, it quite often happens thatmanycamera photo lamp control circuitsfail to operate reliably. Thishasbeen due to the buildup of oxidized'and'corrosive,surface filmson theswitch contacts of little or minima1ly-used mechanical switches employedin such circuits. To' breakdown such surfacefilms (where they areallowedto buildup) -r equires higher voltage. lf'only 3 volts areavailablefrom the primary energy source, (suchas a battery). the

probability of failure-in operation isquite high. To overcome thisproblem, the present invention was devised.

An additional problem besetting small, hand -held "cameras is the jitteror bounce inducedvinthe camera I by mechanically operable switchescomprising apart of the camera control mechanism. The present invention1 also serves to reduce such jitter, bounce or vibration whereby thechances of obtaininggood picture. quality are enhanced.

It is, therefore, a primary object of-this inventionto provide a familyof new and improved contactfless light emission initiation circuits'foruse incontrollingoperation'of photo lamps employed inlightingsubjects tobe photographed with acamera. i 1

Another object of the invention is to provideflsuch' contact-less photoa lamp light emission initiation circuits which may be fabricated inmierominiaturized integrated circuit form, are capable ofreliableoperation' with low voltage electric energy sources, and may beincludedasoperating subsystems of an-overall camera control system forcontrolling light emission synchronously with the controlled exposure ofthe film plane of the camera. v i

lightthroughthe optic system of a camera with which the photo lamplight'emission initiation circuit is used. In one embodiment of theinvention, the photo lamp means may. comprise an array of photo lampshaving control circuit means for selectivelylighting desired ones of thephoto lamps and the contact-less .photo lamp light emission initiationmeans initiates the operation of thecontrol circuit means forselectively lighting a-desiredone,of the array of photo lamps. Ifdesired, a

mechanical on-off switch maybe connected in circuit relationship thecontact-less photo lamp light emission initiation means for selectivelyenabling the circuit for operation and preserving theenergy of thelow'voltage electric energy source during periods of non-use; however,such mechanical on-off switch is constructed .so that itis readilyself-cleaning by involving high forces. *If the photo lamps areof aflashbulb type-,they may bepositioned in the circuit intermediate thesource of electric energy. and the contact-less photolamplightemissioninitiation means so. as to serve as:thelon-oftdswitchinthemanner of an electric fuse.

In another preferred-embodiment of theinvention, an exposure controlcircuit may be included in -a control systemalong with the'lightemission initiation circuit for controlling the extent of exposureof the film plane ofthecamerato a subjectbeing photographed inconjunction with light emitted by the photo lamp means, and such-asystem includes means for synchro nizing operationof theexposurecontrol'circuit with theoperatiojn of the contact-less photolamplight emission initiation=meansi In a still further arrangementaccording to the-invention, the photo lamp means em-v 1 ployed may.comprisean array of photo lamps having control circuit-means forselectively lighting desired ones of the photo lamps and'thecontact-less photo v lamp light emission initiationmeansinitiatesoperation ofathe'controlcircuit means for selectivelylighting adesired one of the may" of photo lamps. ln'all uch cameracontrol systemarrangements, the circuit components preferably are fabricated inmicrominiaturized f integrated circuit form.

- According to'the particular applications in mind, the

.contact-less'photolarnp light initiationmeans may be magneticallyoperated, it may be radiant energy operated either by light or alphaparticle radiation or the like, or it may-be pressure responsive.Several different forms. of these basically different contact-less photolamp light emission initiation means are disclosed.

' Other objects, features and many of the attendant ad-. vantages ofthisinvention will be appreciated more readily as the same becomesbetter understood by reference to the following detailed descriptionwhen considered in connection with the accompanying drawings, whereinlike parts in each of the several figures are identified by the samereference character v and wherein:

FIG. l'is a schematic circuit diagram of one form of a new'and improvedphoto lamp lightemission initiation'ciruit constructed in accordancewith the invention; 1

FIG. 2 is a schematic circuit diagram of still another form of acontact-less light emission initiation circuit according to theinvention and which employs a pres sure responsive initiation means;

FIG. 3 is a schematic functional diagram illustrating one form ofmechanizing the circuit arrangement depicted in FIG. 2; I 1

FIG. 4 is a schematic circuit diagram of a magnetic sensitivecontact-less photo lamp light emission initiation circuit constructed inaccordance with the invention;'

FIG. 5 is a schematic circuit diagram of still another form of magneticsensitive contact-less emission initiation circuit employing a magneticsensitive diode;

FIG. 6 is apartial perspective view of a portion of a camera shuttermechanism illustrating the manner in which such mechanism can bemodified to include either a permanent magnet or a light opening forcontactless initiation of a magnetic sensitive diode or a lightsensitive diode;

FIG. 7 is a schematic circuit diagram of still another control of theexposure of the film plane of a camera;

FIG. 15 isa schematic circuit diagram of an embodiment of the inventionemploying a light emitting diode as part of the contact-less lightemission initiation means;

FIG. 16 is a schematic circuit diagram of a. different form of thecontact-less light emission initiation circuit employing a lightemitting diode and light activated silicon control rectifier to initiatelight emission in a contact-less manner; s

FIG. 17 is a schematic circuit diagram of still a third form ofcontact-less light emission initiation circuit employing a lightemitting diode and including a capacitor for conserving energy of thelow voltage electric energy source employed for circuit energizationpurposes; and

FIG. 18 isa schematic circuit diagram of a modification of the circuitof FIG. 4.

FIG. 1 is a schematic circuit, diagram of a contact-less photolamp'light emission initiation circuit constructed in accordance withthe invention, and which employs a pressure sensitivestrain gaugeelement shown at 11 as a contact-lessphoto lamp light emissioninitiation means. The pressure sensitive element 11 may comprise anyknown form of pressure or strain sensitive device which changes itselectrical resistance in response to the application of a pressure orstrain to its pressure sensitive area. The pressure sensitive element 1l is conform of contact-less light emission initiation circuit accordingto the invention which employs a magnetic sensitive I-Iall element andamplifier arrangement;

FIG. 8. is a functional block diagram of themagnetic sensitive Hallelement and amplifier employed in the I circuit arrangement of FIG. 7;

ement that can be employed to provide certain delay functions in theoperationof a light emission initiation circuit employing such' anelement;

FIG. 1 1 is a series of characteristic curves illustrating the intensityof light emitted vs. time characteristic of nected in series circuitrelationship with a load resistor 12 across a'pair of power supplyterminals 13 and 14 that in turn are adapted to be.v connected across asource of electric energy 15. The source of electric energy 15 maycomprise any known portable source of electric energy but preferablycomprises a low voltage battery having a terminal output voltage ofapproximately 3 volts or less and a short circuit current of about 2amperes, although the circuit is in no way restricted to use only withenergy. sources of this voltage rating. With the circuit thus comprised,a conventional mechanically operable on-off. switch 16 is included inthe series circuit comprising pressure sensitive element 11. and loadresistor -12.'For areason to be explained I more fully hereinafter, theon-ofi' switch 16, if needed, I should be located in a position so thatits variable on a light emission initiation circuit employing thecircuit FIG. 14 is a functional block diagram of still different andimproved camera control system a'ccording'to the invention whichprovides synchronized contact-less light emission initiation, controlover the flashing of selected ones of an arrayof photo lamps, andelectronic resistance would have minimum effect. As an alternative theswitch 16 can be eliminated and a switch shown in dotted outline formcould be included in the circuit in place of switch 16. In either case,higher forces and self cleaning result as compared with norm shutteroperated contacts at low level. r In additionto the above-mentionedcircuit components, the power supply terminals 13 and 14 also areconnected across a series circuit branch formed by a photo lamp meanscomprising a socket or a plurality of sockets for receiving thebase of aconventional photo lamp'in the photo lamp means is connected in seriescircuit relationship with the load terminals of a gate operatedsemiconductor switching means 18. The photo lamp means may comprise aconventional bayonet type receptaclefor receiving a single photo lampflashbulb such as the M5 or M2 flashbulbs or the A G-l flashbulbmanufactured and sold by the Photo Lamp Department of the GeneralElectric Company or some similar photo lamp. The photo lamp means alsomay comprise the or the photo lampmeans 17 may even comprisean'integrated circuit type of lighting control shown in dotted outlineformat 19 for selectively controllingjthe lighting or flashing ofdesired onesof an array of photo lamps such as shown in dotted outlineform at 21a, 21b, etc. Thus, it will be appreciated that thephoto lampmeans 17 employed in the embodiment of the invention shown in FIG. 1 aswell as in other'embodiments of the invention to be describedhereinafter, maycomprise any one of the above-listed devices and/or thereceptacles or sockets for receiving such devices. It is to beunderstood, therefore, that while only a single photo lamp 17 will beshown in the remaining embodiments of the invention disclosed herein,such depiction is in-' tended to include any of the above-mentionedphoto lamp means and similar devices. I

The gate control semiconductor switching means 18. may comprise aconventional gate control silicon con-.

trolled rectifier (SCR), a silicon. unilateral. switch SUS), aprogrammable unijunction transistor (PUT),

a silicon bilateral switch (SBS), a complementary uni- I on-off switchcontacts 16 being closed and the applica tion' of a sharp striking blowor other means for suddenly increasing the pressureon the pressuresensitive surface of element 11, the current'flowing through the loadresistor 12 will be sharply increased. The coupling capacitor 22operates to convert the sharp increase in voltage appearing across theload resistor l2to a gating current applied to the gating electrode ofthe semiconductor switching device 18 to render it conductive andthereby supply a light'ernission initiating current'flow through thephoto lamp means l7.

As was notedearlier, the on-ofi' switch 16 is physically located in apreferred position such that its switch thereafter supplies the mainlight flash initiating cur- I rent through the photo lamp 17. I If thephoto-lamp 17 comprises a conventional, ex-

. pandable photo flash lamp of the General Electric M-2 type, it willrequire about 1 ampere of current at 0.7 of a volt to assure reliableflashing. With the circuit arrangement shown in FIG. 1, flashing currentand voltage of this magnitude is assured since with the semiconductorswitching device 18 gated on in its conducting condition the forwardvoltage drop through the device is only'a fraction of a volt. From aconsideration of the circuit shown in FIG. I, particularly where theon-off switch 16 is included in the circuit branch with element 11 andload resistor 12'and is not connected intermediate the low voltagebattery source 15 and the photo lamp 17, substantially the full voltageof the source 15 minus only the forward drop of the semiconductorswitching device 18 is applied across photo lamp 17 to assure reliableflashing of the photo lamp. It should be noted that with eitherarrangement employing the onoff switch 16, or the alternativearrangement shown in'dotted outline form at 716a, it is neces- -sarythat the switch contacts be readily accessible for of the gatecontrolled semiconductor switching device contacts do not carry fullcurrents and low contactresistance is not a'requirernent. Also,'sinceeither 16 or 16a are not tied in with the shutter they are more suc-'.

cessfully cleaned by the unskilled; This arrangement is in contrast tomany prior art devices wherein mechanically operable, on-off switchcontacts are mounted and operate synchronously with theshutter mechanismof the camera, etc., and must be located in a position within the cameraso as not to be accessible for cleaning. Assuming therefore that theswitch contacts 16 are cleaned-so as not to constitute a considerableincrease cleaning so asto minimize any voltage drop across the switchcontacts. l

It may be necessary to include a mechanicalon-off switch in thecontact-less light emission initiation circuit shown in FIG. 1 due tothe fact-that withoutsuch I a switch, current could continuously flowthrough the pressure sensitive resistance element'll' and load resistor12 and ultimately bleed off the energy of the battery source '15.However, the high foff resistance of semiconductor 18, and certainpressure sensors 11 could result in leakages less than the normalbattery leakages and thus would result in life approaching shelf life.In-

all events, it willbe seen that the electric current flow required toinitiate light emission from the photo lamp is developed internallythrough intemal operation of the pressure sensitive resistor element vllso that only a minute current flow will suffice to initiate conduction18. Because of this internal generation or development of the requiredlight flash initiating current, and the fact that such current is notrequired to puncture an'ex- ,ternal oxidized or other corrosively coatedsurface film formed on a set of switch contacts, the circuit arrangementcan be said to be contact-less in naturein that it possesses lessvulnerable contact resistance than previ- 'ously available lightemission initiation circuits;

Pressure transistors with high ofi-resistances are presently more commonthan 2 terminal pressure de- 1 vices with similar properties. Thus, anarrangement such as shown in FIG. 2 of the drawings may be em- I ployedto'avoid all switches. The circuit arrangement shown in FIG. 2 iscomprised by a contact-less photo lamp light emission initiation means25 connected in series circuit relationship with a load resistor 12across in resistance, and ifa low voltage batterysource 15 is employedhaving a voltage on the ord r of 3 volts, sufficient current will besupplied through the load resistor 12 to gate on the SCR or othergate-controlled semi conductor switching device l8. For this purpose,some thing on the order of 20 200 microamperes of gating current must besupplied to the gate electrode of the switching device 18. It will beappreciated, therefore,

, that only a minute amount of current is required to trigger on thegate control switching device '18 which the power supply terminals 13and 14 which are designed to be connected across the load terminals of alow voltage battery source 15. The contact-less photo lamp lightemission initiation means 25 comprises a pressure sensitivesemiconductor device such as piezoelectric pressure transistor similarto that offered for sale by the Stow Laboratories of Stow, Mass,announced in the Electronics Magazine, January 23, I967 issue. Thepressure sensitive transistor 25'includes a pressure sensitive area 36that is exposed to a small cap The juncture of the load resistor 12 andpressure sen-- sitive transistor is connected to the control gate of asemiconductor switching element 18 such as an SCR, SUS, etc., that inturn has its load terminals connected in series circuit relationshipwith the receptacle for re ceiving a photo lamp means 17 which of coursemay comprise either a single photo flash lamp or similar de receptacleitself is external of the camera or other housing for the light emissioninitiating circuit, j and hence can be cleaned readily by auser of theequipment should-the abrasive cleaning action of the insertion andremoval of the photo flash lamp not prove sufficient. For these reasonsthe contact-less photo lamp light emission initiation circuit shown inFIG. 2 is highly reliable in operation even with very low voltagebattery sources.- 7

FIG. 3A of the drawings illustrates one form of a mechanical actuatingmechanism for applying pressure or stress to a stress'sensitive area ofthe semiconductor element 25. In this arrangement, a pushbutton 31foracvice. It is necessary in the circuit of FIG. 2, however,

that the photo lamp means 17 be of the photo flash type which burns outor open-circuits upon being flashed. With this arrangement, thephotoflash lamp 17 will function as an on-off switch in the manner of a fuseto open the circuit connection through the load terminals of the gatecontrol semiconductor switch 18 after being flashed. This is importantsince the gate controlled semiconductor 18 is of the thyristor typewhich once being gated into conduction remains in conduction until thecurrent flowing through the device hasbeen,

reduced below a minimum holding value. Upon this 00,-

casion, the device will re-assume its blocking condition u'ntil againgated on by the application of a gating signal to its gating electrode.Thus, it will be seen that; the

With the circuit arrangement shown in FIG. 2, it i should be noted thatwith respect to the gating on circuit element comprised by thecontact-less, pressure sensitive transistor 25, load resistor 12 and lowvoltage 1 battery source 15, there are no mechanical on-off switchcontacts in this circuit branch.The light emission initiating switchingaction takes'place internally in the pressure sensitive semiconductorswitching device 25 upon the cap or anvil 26 contacting the pressuresensitive area of the semiconductor device 25 as shown' in FIG. 3. Thus,the light flash emission initiating current need not'puncture or passthrough a .high resistance film in order to develop the desired lightemission initiating gating on current pulse to be supplied to thecontrol gate of the semiconductor switching device 18. Similarly, theswitching device 18 operates only through intemally'protected currentpaths to supply the'light flash initiating current to the inputterminals of the photo flash lamp 17. The only contact surfaces in thecircuit arethose provided by the socket or receptacle in which the photoflash lamp 17 is secured. These contact surfaces normally will besubjected to a cleaning action by reason of the insertion and removal.of the photo flash lamp base into theireceptacle under high forcelevels. Additionally, it should be noted that the tuating a cameraassociated with the light emission-initiation circuit, is attached to alever arm 32 pivoted at a point 33 against the action of a return spring34. An anvil 35 is formed on one surface of the lever arm 32 and hasthecap 26 attached thereto at a point directly opposite the pressuresensitive surface 36 of the pressure sensitive semiconductor element 25.The end of lever arm 32 operates against a cam surface 37 of a shutter38 which normally closes the aperture shown at 39 used to expose thefilm plane of the camera. Upon the pushbutton 31 and lever arm 32 beingdepressed by auser of the camera, the anvil 35 and cap 26 will bebroughtinto contact and will apply stress or pressure to the pressuresensitive area of the semiconductor de vice 25 thereby initiatingcurrent flow through the device and hence photo lamp :17 of FIG. 2 inthe manner previously described. Simultaneously with this action, thecam surface 37 will cause the shutter 38 to bepivoted to the positionshown in dotted outline form thereby exposing the aperture 39 and hencethe film plane of the camera.

'The mechanical angular relationship of the opening of shutter 38 to thepoint where the cap 26 on anvil 35 strikes pressure sensitive transistor25 is such that the opening of aperture 39 occurs after a short delayperiod related to the time required for the flash bulb to emit its peakintensity of light. This relationship is depicted in FIG. 3B of thedrawings wherein the percent opening of the aperture 39 is plottedagainst time. From a review of FIG. 3B it will be seen that the percentopening of aperture 39 goes from 0 value to a I maximum value after'aperiod of about 10 milliseconds following depression of the pushbutton31. The curve shown in FIG. 38 also could be employed to illustrate theemission of light characteristics of the photo flashbulb where theintensity of light is plotted as the ordinate and the time required toemit a given amount of light is plotted as the abscissa. It will be seenthat the mechanical relationship of the opening of the aperture v 39 isdesigned to coincide substantially with the maximum light intensityemission of the photo flash lamp 17 with which the circuit is designedto be used. It might also be noted that while in FIG. 3 the cap 26 isshown as being mounted on anvil35, the mounting of the cap v on thesemiconductor surface 36, orother similar alternatives also couldreadily be achieved. a

' FIG. 4 of the drawings isa schematic illustration of still anotherform of contact-less photo lamp light emission initiation circuitemploying a magnetic sensitive diode 41 as the contact-less photo lamplight emission initiation means. The magnetic sensitive'diode 41 isconnected in series circuit relationship with a load resister 12 acrossthepower supply terminals 13 and 14 and through on-off switch 16 to theelectric energy v 9 source 15 which may comprise a low voltage batteryof about 3 volts. The magnetic sensitive diode 4lmay be similar to theone manufactured and sold by; the Sony tivev Hall element or othermagnetic sensitive semiconductor device could be employed in place ofthe diode 41 as will be described more fully hereinafter. Similar toearlier described circuits, the juncture of the magnetic sensitive diode41 and load resistor 12 is coupled through a coupling capacitor 22 tothe control gate of the semiconductor switching device 18 such as anSCR, SUS, etc. The load terminals of the switching device 18 in turn areconnected in series with the photo lamp means 17 for selectiveenergization in themanner described hereinafter.

A rotatable shutterplate 42 which is spring biased to rotate in acounterclockwise direction as shown by the arrow 'includes an apertureopening shown at 43 which upon rotation into alignmentwith the apertureorpassageway providing an opticpath to thefilm plane of a camera (shownat 44), will'operate to'expose the film plane to a subject beingphotographed. The shutter plate 42 can be pre-wound be means of atrigger mech anism (not shown) by an operator of the camera and isprevented from unwinding by a stop 45 formed on its periphery. In thepre-wound condition, the stop 45 is engaged by the .end of a releaselever arm 46 that in turn is actuated by a pushbutton 47. Upon thepushbutton" 47 being depressed against the action of .a return spring48, the end of lever arm 46 allows the rotatable shutter member 42 to berotated in the direction shown bythe arrow. t

The rotatable shutter plate 42 also includes a permanent magnet shown at49 which is mounted on its periphery and which is adapted to influenceor magnetically permeatethe magnetically sensitive area of themagnetically sensitive switching element 41 upon being rotated in thepreviously described manner. It is desir-, able that themagneticenergization of the magnetically sensitive semiconductor diode 41' takeplace slightly in advance of the aperture opening 43 becoming alignedate in the manner of a fuse. However, for such anarrangement, the photolamp17 would have to be of a filament type which will allow sufiicienttrickle current to flow through its filament to render the diode 41conductive. v

After conditioning the circuit of, FIG. 4, an operator of the-camera isthen ready to trip the camera for pictur'etak ingpurposes Upon thisoccasion, the pushbutton 47 is depressed thereby releasing the rotatableshutter 42 in the above briefly described manner. This results inaligning the magnetic field of the pennanent magnet 49 (at leastinstantaneously by reason of the rotational scanning of the field of thepermanent magnet past the magnetically sensitive semiconductor diode 41)so as to trigger the diode 41 intoconduction. This results in theproduction of a current pulse in the gateemitter circuit of SCR 18'byreason of the co-action of the load resistor 12 and coupling capacitor22 and triggers the semiconductor switch 18 into conduction therebyigniting or flashing the photo lamp 17. As previouslystated by reason oftheir relative angular location on rotatable shutter 42, flashing of thephoto lamp 17 is initiated somewhat in advance of the aperture opening43 exposing theaperture 44 and hence film plane of the camera so thatsuch exposure coincides substantially with the maximum or peak intensityof the light emitted by the photo lamp 17..It will be appreciated,therefore, that the resulting light flash initiation is derived throughinternal action of the magnetically sensitive semiconductor, diode 41without requiring that the low voltage. source 15 provide sufficientenergy to punch through anyoxidized or corrosive surface film with theaperture 44 so that upon the latter occurrence,

the light emitted by the photo lamp 17 has reached substantially itspeak intensity. This can be accomplished by appropriate design of theangular location of the permanent magnet 49 on'therotatableshutter plate42 relative to the positions of the aperture opening 43 on theshutterplate and the aperture 44 which is of course located on -a differentpart of the camera and is in a fixed position relative to the rotatable.shutter plate 42.

In operation, the circuit of FIG. 4 functions in the fol- I lowingmannerqln this description, it is assumed that an operator has inserteda photo lamp 17 in the socket designed to receive such photo lamp andhas pre-wound or cocked the camera so as .to condition the rotatableshutter plate42 to be rotated through theaction of a pre-wound spring(notshown) in the manner described, I above. If a mechanical on-offswitch 16 is located in the .circuit as indicated, it would then beclosed to condition the circuit for operation. However, it should benoted that the circuit could be modified to eliminate the on-off switch16 by placement of the photo lamp 17 the 'on-off switch 16 (sould it beused as shown in FIG.

4) can be designedto be selfcleaning and operable at high force levels.Thus, it will be appreciated that the magnetically sensitive diode 41constitutes another 7 fonn'ofconta'ct-l essphoto lamp light emissioninitiation means according to the invention.

- FIG. 50f the drawings is a schematic illustration, of

a contact-less light emissioninitiation circuit which has beenconstructed using the trigger mechanism (shown in FIG. 6) along with-theother components of an Eastman Kodak model 134 lnstarnatic" camera. Thisparticular camera includes an electro-optic exposure contr'ol'shown at51 which operates in conjunction with a light source 52 through themedium of anintermediate.

switch contact 53 that is closed initially upon the oper- ,atorof thecamera depressing the pushbutton 47 against the action of a returnspring 48. The closing of the intermediateswitch contact 53 onto aswitchconthe exposure control circuit 51 and to a light source 52' tact54 formed on the pivoted lever arm 55. (with the pushbutton 47 in thedepressed position), allows electric current from the electric energysource 15 (which may comprisea low voltage battery source) to flow to toindicate to theuser of the camera that the battery source 15 is working,and that the exposure control 51 r is energized. The exposure control 51then operates autr'ol circuit 51 the pushbutton 47 will continueits'travel tomatically inthe manner of a photometer to set the apertureopening of the camera in accordance with ambient lighting conditions. I

Subsequent to the energization of the exposure condownwardly so as toclose the intermediate switch contact 53 onto a third switch contact 56.Contact 56 includes an extension 57 that operates against the end 46a ofa centrally pivoted lever arm 46. The remaining end of the centrallypivoted lever arm 46 operates to stop the rotation of a rotatableshutter member 42 as was described previously in connection with FIG. 4of the drawings. The rotatable shutter member 42 is acted upon by apro-wound spring (not shown) which tends to rotate the shutter member 42counterclockwise in the direction of the arrow. Mounted on the rotatableshutter member 42 is a permanent magnet 49 and an aperture opening 43 isformed in the member for exposing the aperture 44 shown in dottedoutline form to thereby expose the film plane of the camera. Thisportion of the circuit operates in precisely the same man net as theembodiment shown in FIG. 4.

Upon an operator of the camera placing the camera in condition for thetaking of a picture, he will have pre-wound the spring that drives therotatable shutter member 42, inserted an unused photo flashbulb 17 inthe socket for receiving the same and properly lined up the cameraforthe taking of a picture. Thereafter; upon depressing the pushbutton47, the following sequence of operations will occur. First, during theinitial portion of the downward travel of the free end of the pivotedlever arm 55, the switch contacts 54 and 53 will close soas to energizethe'exposure control 51 and the indicause the extension 57 to rotate theend 46aof lever arm 46 downwardly in a counterclockwise direction so asto release the end 46 from the stop 45. The prewound spring will rotatethe shutter member 42 in a counterclockwise direction shown by the arrowso asto align the magnetic field of the magnet 49with the magneticallysensitive, contact-less, photo lamp light emission initiation meanscomprised by the magnetically sensitive diode 41. This results in theproduction of a gating-on current in the gate-emitter of thesemiconductor switch means 18 causing it to be rendered conductive andto supply a light emission initiating current to the filament, fibrousmaterial, gaseous material, or

other light emission substance in the photo lamp 17. As I statedpreviously, the relative positions of the, per'ma nent magnet 49 and theaperture opening 43 on the ro-' tatable shutter member 42 arepredesigned to allow coincidence of peak or maximum light emission withthe exposure of the aperture or other optic path opening to beingadvanced, it will automatically cock the trigger plate 69 into itspreset or wound condition shown in cludes a shutter plate 61 which isrotatably suspended v by a pivot 63 over an aperture of the camera shownat 44 formed in a back supporting plate 62. The shutter 12 plate 61includes a spring tensioning arm 64 which is acted upon by a wiretension spring 65 supported between the pivot 63, the tension arm 64 anda pin 66 secured to the back supporting plate 62. The springis arrangedsuch that in its normal, quiescent condition, the

shutter plate 61 is supported in the position shown 'inv supportingplate 62. The extension supporting surface 68 has rotatably mounted onit a trigger plate 69 having an amplifying am 71 which is designed toengage the trigger arm 67 of the shutter plate 61 and to rotate it in aclockwise direction from its quiescent position shown in FIG. 6. Whenthe trigger arm 67 is rotated clockwise by the amplifying arm 71,aperture 44 will be exposed allowing the image of an object being viewedby the camera to be projected through the optical path provided by theaperture 44 to the film plane of the camera, in a well-known manner. Toassure proper operator controlof the opening of the shutter plate 61,the trigger plate 69 is designed to be'rotated clockwise from theposition in which it is shown in FIG. 6 to the dotted line positionshown. When this. prewound or cocked, the amplifying arm 71 is engagedbehind a release pin 72 formed on a cantilever arm 73 pivotablysupported at 74 and tensioned in an upward position by the action of abias spring 75. The bias spring 75'holds the cantilever arm 73 in itsupward position so that the stop 72 prevents the amplifier 'arm 71 fromrotating into engagement with the trigger 67 of shutter plate 61. Thetrigger plate 69 is rotated into its cocked or set condition by means ofa conventional film advance and cocking mechanism (not shown) having awiper arm shown at 76 that engages an upwardly ex tending tab 77 formedon the trigger plate 69. Trigger plate 69 is rotated around the pivotpoint 78 against the action ofa hair spring shown at 79 supportedbetween a pin 81 secured to the surface 68, or some similar fixedsurface on the housing of the camera, and a pin 82 secured on thetrigger plate 69. I

-With the above arrangement, upon the camera film dotted outline formagainst the action of the hair spring 79 which tends to return thetrigger plate to its quiescent condition shown in solid lines in FIG.-6.The magnetic diode shown at 41 in FIG. 5 is mounted on the camerahousing in a position closely adjacent the trigger plate 69 and apermanent magnet 49 is secured to the trigger plate 69 in a' positionsuch that its magnetic field will sweep past and act upon the magneticsensitive diode 41 upon the trigger plate 69 traveling from its cockedor wound position shown in dottedoutline form'to its quiescent conditionshown in solid form in mum light intensity produced by photolamp 17 is rl3 achieved substantially concurrently with the full opening of theaperture 44 by theshutter plate 61 y In operation, it will be seenthatupon the film of the camera being advanced to a new, unused portion, thefilm advance and cocking mechanism automatically will cock the triggerplate 69 to its prewound condition shown in dotted outline form. Inmoving to this condition, the amplifying arm 71 will be enabled to rideover the tapered or curved surfaces of the release pin 72 and triggerlever arm 67. A stop or pin 83 prevents the shut ter plate 61..frombeing rotated counterclockwise to a 7 position sufficient to expose theaperture 44 during the cocking or film advance operation. There, theamplifying arm 71 will be blocked in back of release pin 72 until suchtime that the operator of the "camera depresses the pushbutton 47.Atthis point, the amplifying arm is swept to its solid line position bythe action of hair spring 79 thereby rotating lever arm 67 and shutterplate 61 in a clockwise direction, triggering the magnetic sensitivediode 41 and exposing the aperture opening 44 in the above-describedmanner.

I plifier 88 will be triggered into conduction at a point,

43 is formed in the rotatable member93 at an angular position such thatit will coincide with the aperture or other optical coupling path, tothefilm plane of the camera such as is sho'wn in dotted outline form at44. Here, again, the'arrangement is such that the magneti callysensitive Hall element and integrated circuit amsuch that maximum lightintensity is produced bythe photo lamp means 17 substantiallysimultaneously with the exposure of the aperture 44 by ap'erture opening43. However, because no large mass in the form of a I permanent magnetis attached to a'movable part, the

dynamic performance of the apparatus can be im- The embodiment of theinvention shown in FIG. 6

possesses certain undesirable characteristics in that it requires the'use of a relatively high mass permanent magnet 49 to be mounted uponthe movable trigger plate 69. This requirement in'itself tends to limitthe speed of response of the overall trigger mechanism and adverselyaffects its performance. To avoid this possible limitation, anarrangement such as shownin FIG. 7 may be employed. In FIG. 7 a photolamp means 17 is designed to be energized from'a'low voltage source of 7electric: energy comprised bya battery l5 .through power supplyterminals 13 and 14 and the selective switching action of acontact-less, magnetic sensitive,

integrated circuit Hall element and amplifiershown at 88. Theconstruction and operation of the magnetic sensitive Hall element andintegrated circuit amplifier 88 will be described more fully hereinafterin connection with FIG. 8 of the drawings. However, for the pur-, poseof the present description, it is believed to be sufficient to point outthat this element is magnetically sensitive and can be designed toprovide a sharp output current pulse in response to the application of amagnetic field to the magnetic sensitive areas of the element. i

A permanent magnet 89 having a pair of magnetically permeable legs 9land 92 positioned with the legs 91 and 92 straddling the magneticallysenstive Hall element and amplifier 88. A magnetically permeablerotatable member 93 which may be in the form of a very thin disc ofmagnetically permeable material, is secured I so that its peripherynormallyis disposed opposite the ends of the legs 91 and 92. While thusarranged, the rotatable member 93 serves to short circuit or bypass thelines of magnetic flux from the ends of the legs 91 and 92 around themagnetically sensitive Hall element and integrated circuit amplifier 88.Aslot shown at 94 is FIG. 4 and other figures of the drawings. Anaperture proved. v

FIG. 8 is a functional block diagram of the construction of theintegrated "circuit, magnetically sensitive E Hall element andintegrated circuit amplifier shown at 88 in FIG. 7. The Hall elementemployed in this structure, is shown at l0l and may comprise a combinedmetal oxide surface semiconductor Hall element and amplifier of the typedescribed in US. Pat. No. 3,524,997, issued Aug. 18, 1970, for aMonolithic Integrated Phase Control CircuitZ John D. Harnden, Jr., et'.al., inventors, and assigned to the assignee of the present invention.The Hall element is a well-known magnetically sensitive device having aconducting channel or inversion layer extending between a source anddrain electrode. Upon a strong magnetic field on the orderofabout 2kilogauss beingapplied perpendicular to the-current flow of thedevice,it produces through the medium of the well known Hall Effect, avoltage component which is mutually perpendicular-to both the currentflow and the'magnetic field, and is proportional to the product of the.current and the magnetic field. This output voltage is supplied to asuitable signal-shaping circuit 102 which may comprise a field effecttransistor. amplifier circuit whose output in turn supplies a poweramplifier stage 103. The power amplifier stage 103 may itself comprise adevice such as a silicon control rectifier (SCR), a PUT, a SUS, or otherknown power amplifier device and may be directly connected in circuitrelationship with the photo lamp means 17 andbattery source 15 forcontrolling electric current flow through the photo lamp means 17 shownin FIG. 7. All of the elements 101, 102 and 103 of the overall circuitstructure 88may be fabricated in mono lithic integrated circuit form soas to be readily mounted within the housing of a hand-held camera. For

a more detailed description of the construction and operation of theHall element magnetic sensor and integrated circuit amplifier structure,reference is made to the above-identified U.S. Pat. No. 3,524,997.

FIG. 9 is a schematic illustration of still another form of magneticallytriggered, contact-less, light emission initiation control circuitconstructed in accordance with the invention. In the embodiment of theinvention shown in FIG. 9, a magnetically sensitive semiconductor switchelement shown at l05controls the initiation of light emission from aphoto lamp means 17in the manner described above. For example, thesemiconductor switch element 105 may comprise either a magneticallysensitive diode, a magnetically sensitive transistor, such as thatdescribed in (LS. Pat. No. 3,389,230, or a magnetically sensitive Hallelement together with associated integrated circuit amplifier elements.A rotatable permanent magnet trigger member shown at 106 is positionedover the semiconductor switch element 105 and includes an apertureopening 43 that is rotated into alignment with an aperture shown indotted outline form at 44, upon the rotatable member 106 being rotatedin a counterclockwise direction as shown by the arrows. Thereleasemechanisrns and spring drive mechanism forrotating member 106 arenot shown for purposes of simplifying the description. The rotatabletrigger member 106 includes apole piece 107 which upon being alignedwith a coacting pole piece 108 disposed adjacent the semiconductorswitch element 105, causes the semiconductor switch element to betriggered to its conducting condition as described previously. In thearrangement shown in FIG. 9, however, the linear position of pole piece108 is physically adjustable to different locations such as shown indotted outline form at 108a whereby the particular point at which thesemiconductor switch element 105 is triggered into conduction relativeto the angular position of the aperture 43 with respect to the aperture44, can be adjusted physically by a user of the flash initiation controlcircuit. This can be achieved by a simple sliding support for the polepiece 108 which is calibrated in terms of time delay so as to achieveeither minimum or maximum delay of the light emission relative to thealignment of the aperture opening 43 over the aperture 44. By thismeans, the user of the camera can control to a greater degree the timingrelation between the pulsed maximum intensity light out put from thephoto lamp means 17 relative tothe opening of the aperture of thecamera. 7

FIGS. 10 and 11 of the drawings illustrate still another form of theinvention wherein by suitable fabrication of the semiconductor switchelement employed in the arrangement of FIG. 9, and proper disposition ofseveral magnetically sensitive areas on a semiconductor substrate toform a multiple semiconductor switch element such as shown at 111, aselectable built-in time delay can be obtained wherein an operator of acamera can by appropriate choice of an output terminal, achieve any oneof a plurality of different time delays relative to the opening of theaperture of the camera. For example, if a semiconductor switch elementsuch as111 has formed, on its substrate three different magneticallysensitive switch areas 112, 113, 114, with each respective area havingits own output terminal T is illustrated in FIG. 11 wherein the lightoutputfrom a photo lamp triggered by respective ones of the outputterminals T T and T is plotted vs. time. It will beseen in FIG. 1 1 thatif the operator connects the photo lamp means 17 to the output terminalT the maximum intensity light flash will be produced only about 1millisecond in advance of the opening of the aperture 44 by apertureopening 43. For certain types of pictures, under certain conditions,this kind of exposure is desirable. However, for other conditions, itmay be desirable to connect the photo lamp means 17 to the outputterminal T whereby maximum -,light intensity from the photo lamp wouldbe produced some 2 milli-' seconds in advance of the opening of thecamera aperture. Similarly, by connecting the photo lamp means 17 to theoutput terminal T; a full lOmillisecond delay can be obtained. Theselection of the delay can be made by the, operator in advance of takingthe picture, and is a fixed highly predictable, reliable time delaysince there are .no physical adjustments that have to be madeby. theoperator other than connecting the photo lamp means to the desiredoutput terminal T 'T T T etc. It should be noted that the particulartime delays described are for purpose of illustration only and may bethe embodiment of the invention shown inFIG. 12, a 7

photo lamp means 17 isdesign'ed to be flashed by controlling electriccurrent flow through the photo lamp means 17 from a source ofelectricenergy such as 15.

For this purpose, a magnetically sensitive semiconductor switch element111 is provided having a first mag- T and T then the output flashinitiating signal pulses obtained from each of these areas will havedifferent time delays if the switch element 111 is included in aphysical circuit arrangement such as shown in FIG. 9.,

Thus, with a semiconductor switch element such as 1 11, no physicallymovable parts are required to obtain different timed output signalpulses for producing light flashes in different time sequence relativeto the open ing of the aperture of the camera.

For example, assuming the switch element 111 were inserted physically inthe circuit of FIG. 9, it will be seen that as the pole piece 107 isbeing rotated counterclockwise sequentially scans across themagnetically sensitive switch areas 112, '1 13, 114-in that order. Thusit will be-seen that an electric output signal pulse will 'be producedat 112 some 10 milliseconds (for examnetically sensitiveswitch area 112connected to control electric current flow through the photo lamp means17.

.A second magnetically sensitive semiconductor switch area 1 13 isformed on element 111 and is connected to control energization oractuation of a relay winding 1 15 that then in turn controls release, oractuation of a rotatable shutter wheel 42 having an aperture opening '43thereinfor controlling exposure of the film plane of i the camerathrough the aperture 44' shown indotted outline form. This arrangement'may be similar to that employedv on bellows type cameras used forbetter quality picture taking by professional photographers. With suchcameras, it is-necessary to provide some remote control means forsynchronizing operation of the shuttermechanism located at the end ofthe bellows when it is in its expanded conditiomwith the emission .oflight from a photo lamp such as 17.

inwardly from the position shown due to thecontinued depression ofthe'pushbutton 47, the strength of the magnetic field influencing themagnetically sensitive switch area 113 will become sufficiently strongtoren-,

der this switch area conductive. Uponthis occurrence, the relay winding112 controlling the shutter member 42 will be actuated to thereby obtaina synchronized of FIGS. 4 -12. The magnetic light emission initiationcircuitserves to control light emitted from alight source 122.that cancomprise 'a-single photo lamp, an;

array of photo lamps, a flash cube or the like, which emits light whenenergized from asuitable energy source such as 123 under the control ofthe magnetically sensitive, contact-less, light emission initiationcircuit 121. The energy source 123 may comprise a low voltage batterysource, a piezoelectric generator, a

spring wound generator, or other type of knownsmall power source.Operation of the magnetically sensitive light emission initiationcircuit 121 is under the control of a pushbutton switch 124 thatdepresses a permanent magnet 125 so as to cause its magnetic fieldjtoinfluence the magnetically sensitive area of theinitiation controlcircuit 121. This occurs upon the Ipushbutton 124 being depressed so asto bring the permanent magnet 125 from the solid line position shown inFIG. 3

down to the first dotted lineposition shown at 125a. Upon, thisoccurrence, the magnetically sensitive light emission initiation controlcircuit l2l will function in the previously described manner to causethe photo lamp means122 to be energiz'ed,.and emitlightfor lightingasubject to bephotographed;

Further depression of the pushbutton 124 will cause the permanent magnet125 to be moved to its second position shown in dotted outlineformat125b where its magnetic fieldwill influence the magnetic sensitive sur-18 trolled exposure element 127 reference is made to an article entitledGMO A New Optical Material by Professor Terutaro' Nakamura ofthe-University of 1 Tokyo appearing in Technocrat Magazine, vol. 2, No.5,,

shown at 121 and may be constructed according toany 13A of the drawings.

1969, pages 44-46. The device comprises a GMO crystal havingferro-electric properties such that it can be made transparent to lightupon the application of a control. electricfield to its terminals. For amore detailed description of this property, reference is made to theabove-identified article. The device does constitute, however, a solidstate semiconductor type of device so that it allows substantially thecomplete camera control system to be fabricated in accordance with in.

tegrated circuit manufacturing techniques. The device in its unexcitedstate will serve to block all light passage between the lens 128 and thefilmplane 129.'I-Iowever, upon appropriate excitation by an applieddirect current electricfield, thedevice can berendered sufficientlylight'transmissive to form an image of the subject being photographed onthe film plane 129. By controlling the time .duration of this directcurrent exciting field, an appropriate photograph of the image can beobtained. The time duration of the exposure can of course be'controlledby appropriate design of the magnetic initiation andJconversion circuit126 to provide the desired exposure time period as depicted in FIG.

In, operation, .assuming'that the camera has been appropriately loadedwith unused-film, and unused flashbulbs, and has been aligned on asubject to be photographed bya user of the camera, a picturecan berecorded in accordance withthe following sequence. De-.

' pression of the pushbutton 124 first initiates operation of themagnetically sensitive contact-less light emission initiation circuit121 as to. emit light from the photo lens light source 122. This isdepicted in the curve shown inFIG. 13A (1) wherein the .solid linedepicts l. the electric current pulse supplied by the magnetically itrates the intensity of the ensuing light'pulse produced sensitive lightemission initiationcircuit 121 to the photo lamp light means 122, andthe dotted line illusas .a result of the excitation of the photo lamplight I source 122. Continued sequential depression of the 1 down to itssecond dotted line position 125b to thereby face of a second magneticinitiation control circuit shown at 126 The magnetic initiation controlcircuit 126, in place of initiating operation of a photo lamp lightsource such as 122, instead initiates operation of a conversion circuitof conventional construction. The conversion circuitmay be comprised bya push-pull transistor power converter circuit of known construc- Yposure element 127 because it operates as a combined shutter/aperturecontrols both the time of opening, as well as the extent ofexposure ofthe film plane 129 to a subject being photographed through the lens 128.For

a more detailed description of the electricallyconpushbutton 124 bringsthe permanent magnet 125 initiate operation of the. magnetic initiationand conversion circuit 126. This circuit thereafter. functions toproduce an output electric current pulse having the wave shape shown inFIG. 13A (2) to provide appropriate excitation of the electricallycontrolled shutter/aperture exposure control element 127. From acomparison of the time relation of the current pulse shown in FIG.13A(2) to that shown in curve (l), it will be seen that the timedexposure control of the electrically operable exposure controlelement'l27 coincides substantially with the light pulse a lightsource122.

FIG. 14 is a functional block' diagram of an even more completeelectronic control system for a camera wherein the required time delaysbetween operation of the several subsystems of the camera is achievedelectronically. The controlsystem shown in FIG. 14 also is designed foruse with an array of photo lamp means which may be selectivelysequentially flashed. The control system shown in FIG. 14 employsamagnetically sensitive, contact-less light emission initiation circuit121 whose operation is controlled by a permanent magproduced by thephoto lamp net 125 through the medium of a pushbutton 124. Themagnetically sensitive light emission initiation circuit 121 may befabricated in accordance with the teachings of any of FIGS. 4-12, andoperates to supply direct .current energy from an energy source 123 to adelay synchronizing circuit 131: The delay synchronizing cir- 129 isextremely high speed, or the lighting background, etc. produces a highintensity image, the control pulse supplied to theelectricallycontrolled exposure element 127 may be extremely short in duration suchas depicted by the pulses 136a, 136b, etc., to.

' thereby obtain onlya very short time duration exposure cuit 131 may befabricated in accordancewith an'ysof comprise any known transistorconverter circuit, or a SCR, SUS, or other known DC to DC powerconverter of the film plane to the subject being photographed.Alternatively, if the film employed is relatively slow in speed, or thebackground, etc, produces only a very low level intensity image, thetime duration of the control' pulse to the exposure element 127 mayextend out to the point 136], etc. By this means, closed loop controlover the extent of exposure of the film plane to the circuit susceptibleof fabrication in accordance with insor 135 then controls tum-off of theIC converter 134 so as to provide a substantially closed loop control ofthe exposure time of the film plane 129. I

In operation, assuming that a camera employing the system of FIG. 14 hasbeen properly conditioned for the taking of a picture,the operator thendepresses the pushbutton 124. This results in moving the permanentmagnet from the solid line position shown at 125 to the dotted lineposition at 125a and thereby initiatesoperaw' tion of the magneticallysensitive-light emission initiation control circuit-1'21 in the-mannerpreviously de scribed'in connection with FIGS. 4-12 to supplyenergization current to the'delay synchronizingcircuit 131. Delaysynchronizing circuit 131 then supplies a current pulse such as shown insolid form in FIG. 14A( 1) to the array control circuit 132 whichcontains selectively to flash or emit light from 'a desired one of anarray of photo lamps comprising light source 133 as depicted by l thedotted line curve shown in FIG. 14A(l). Concurrently with this action,the delay synchronizing circuit subject being photographed is positivelyprovided to assure acceptable quality image reproduction at the filmplane 129. Because substantially all of the elements of the cameracontrol system shown in FIG. 14 are electronic in nature, theentiresystem is susceptible "to. manufacture in integrated circuit formwhereby it canbe employed in a hand-held camera. Thus, it can beproduced and sold at relatively low cost while assuring relatively highquality image production.

FIG.15 is a schematic circuit diagram of still another different form ofcontact-less light emission initiation control circuit constructed inaccordance with the invention and which employs a light emitting diodeand light activated SCR to achieve contact-less lightemission-initiation. The arrangementrshown in FIG. 5 employs a springwound rotatable shutter plate 42 that automatically is rotated in acounterclockwise direction upon the pushbutton 47 being depressed torelease the end of lever arm 46 from the stop upon the user'of thecamera desiring to snap a picture, all in the. manner previouslydescribed with relation to FIG. 4 of the drawings. Thearrangement'further includes a photo lamp means '17 that may comprise asingle photo lamp, a. fla'shcube, a linear array of flashbulbs, or anarray control circuit selectively controlling desired ones of an arrayof flash lamps, etc., as described previously. The photo lamp means "isdesigned to be inserted into, a

L pressure socketfitting so that it is self-cleaning insertion andremoval of the photorlamp bulbs. The ter- 131 supplies a'delayenergizing pulse to the electrically controlled shutter/apertureexposure element :127 to,

the current pulse. These different trailing edges depict the manner inwhich the time duration of the excitation current supplied to theelectrically controlled exposure element 127 can be varied in accordancewith the setting of the sensor 135 for different. film speeds employedat the film plane 129 or as determined by the intensity or level oflight of the image beingphotographed. Thus, if the film employed atthefilm plane v minals of the socket for the photo lamp means 17 areconnected in series circuit relationship with a source of electricenergy 15 that may comprise a battery, piezoelectric generator, etc. Thesource of electric energy 15 mayieven comprise an expendable paperbattery such as that described by the Norelco Manufacturing Company inrecent literature released by that company.

Theseries circuit comprises by 17 and 15 is con.- nected across a firstcircuit branch comprised by a light emitting diode 141 (referred to as aLEDlconnected in series circuit relationship with a limiting resistor142. The light emitting diode'l4l may comprise any con- 4 ventional,commercially available light emittingdiode such as the gallium arsenidediode manufactured and sold by the Miniature Lamp Department of theGeneral Electric Company, a visible light emitting diode of gal- .liumphosphide also manufactured and sold by the Miniature Lamp Department ofthe General Electric Company, and other such similar devices. Lightemitted by v thelight emitting diode 141 is'intended to pass through aninitiating opening 143 formed in the rotatable shutter member 142 uponthe opening 143 becoming aligned with an opening 144 in a stop. Lighttransmitted from the light emitting diode141 through openings 143 and144 will impinge upon the light sensitive surface of a light activatedsilicon control rectifierl45 re ferred to asa LASC R); v e

The .LASCR is a. conventional, commercially available devicemanufactured andsold by the Semiconduc-f tor Products Department of theGeneral Electric Company and may befabricated in either discrete or integrated .circuit form, and constitutes a second circuit branch connectedinparallel with the circuit branch comprisedby LED 141 and limitingresistor 142. With the circuit arrangement thus comprised, the' photo.

lamp 17 serves as anon-off switchin the mann'er'of an electric fuse andrequires that the bulb notbe placed in the terminal until such time thatthe camera isready for use. Thus, while the circuit is stored on ashelf, etc., between periods of use, the flashbulb should not beinserted in its receiving socketfwhen it is desired to take a picture,the photo lamp '17 is inserted in the receiving socket therebyconditioning thecircuit for the taking of a closed circuit is producedthrough thejcircuit branch including the LED 141*.This device isdesigned to draw a current of about-0.0lampere which is so small asnotto constitute a serious drain on the battery source '15 while the'userof the camera is otherwiseoccupied in aiming, etc., the camera..I-Iowe'ver' it necessary that the photo la'mpll be of thevarietythat'includes a filaelectric fuse-so that a further drain on thebattery does not occur until the new bulb .is placed in the light socketto thereby condition the system to take a new picture. This operationwould be carried out by user of the camera along with pre-winding therotatable shutter member 42 to condition it for the taking of a newpicture.

. a picture. It will be noted, that when thusconditioned,

Should it be d esired, the contact-less light-emission controlcircuitshown at 15 could'be modified by replacing the light emittingdiode 141 and limiting resis-- tor l 42jfwith an alpha particle sourcesuch as that shown in dotted outline form at 146., With the control thusmodified, itis essential that the rotatable shutter member 42 or othershielding member be fabricated of a material which will shield the filmat the film plane of the camera from alpha particle radiation from thesource 146. In operation, the circuit will function in. substantiallythe same manner as describedearlier with relation to the LED version ofFIG. 15, with the excep tion that the alpha particle source 146 nowconstitutes the source of initiating radiation that is directed onto athe radiant energy sensitive 'surfaceof the LASCR 145' m'entfor'supplying the required 0.01 ampere excitation current to LED 141.

When it is desired to take a'picture, the pushbutton I 47 is'released'thereby relea'sin'gthe spring driven rotat able shuttermember 42. Asstated above, the LED 141 already has been energized so that it isemitting' light, l

which under priorconditions has beenblocked by the rotatable shutterplate 42. Upon the shutter plate rotatingthe two openings 143 and 144into alignment, light from LED 141 passes through and impinges upon thelight sensitive surface of the LASCR 145. This results in renderingLASCRl45. conductive and supplying plate 42 in the previously describedmanner. This will result in exposing the film planeof thecamera'substantially concurrently jintime with the production of thelight pulse by the photo lamp v 17.

upon the openings 143 and 144 coming intoialignment'.

Otherwise, the control circuit would function in substantially thesamemanner as described in the preceding paragraphs.

'FIG. 1 s a schematic circuit diagram or an embodiment of theinventionwhich was built employing an Eastman Kodak Model 134 Instamatic cameramodified to'include'a' contact-less light emission initiation controlcircuitshown in FIG. 16. The circuit elements employed in FIG.,16 aresubstantially identical to those described in connection with FIG. 5 ofthe" drawings,

and hence will not be againdescribed in detail. The only differencebetween the FIG. 16 circuit and that shown in FIG. 5 is the substitutionof a light emitting diode 141 for themagnetically sensitive diode 41used in FIG. 5, and the substitution of a light activated SCR 145 forthe conventional gate controlled .SCR 18 and its associated gate controlcircuitry. Another distinction of importance is the inclusion of theadditional initiating openingsl43 in the rotatable shutter member 42 andthe additional opening 144 in a back plate (not shown) but depicted bydotted outline form in FIG. 16.

These additional apertures serve to time or synchronize the exposure ofthe LASCR to light emitted from The voltage vs. time characteristiccurve to the right of FIG. 15 illustratesthe voltage characteristicsofan expendable paper battery of the type described by the NorelcoCompany. It will be noted that this type of battery must be activated bythe user by squashing a suit- I able electrolyte fluid vial in advanceof using the expendable paper battery as an energy source. Following thesquashing of the electrolyte vial, voltage across the battery will risesubstantially in the manner'shown by the characteristic curve shown inFIG. 15. Atsome point indicated by the dotted line, thereafter, thesystem of FIG. 15 may safely be employed by the user of the circuit totake reliable flash pictures,and he will be assured of an adequateenergy source to operate the system in the manner described abovei Itshould be further noted that following the flashing of the photo lampLED 141 and theLASCR 145 (not shown in FIG. 6 of thelight emitting'diode141 as described previously in 1 connection with'FIG. '15 of thedrawings. I

The particular trigger mechanism thatwas employed to'trigger the shutterplate isthe same as that shown in FIG 6 of the drawings anddescribed-previously in connection with FIG. 5. The trigger mechanism ofFIG. 6 when, used with the light activated system of. FIG. 16 ismoditiedto remove the permanent magnet previously described and insertinstead the two openings. l43 'and 144 to allow for timed passage oflight between the the drawings).ln all other respects, the trigger mecha17 it will become open-circuited in the manner of an nism wasconstructed and operates in substantially the same manner as describedpreviously in connection with FIG. 6, and-is substantially the same asthat em- -ployed in a Model 134 lnstamatic camera. e Briefly, however,it will be seen that upon placing the camera control system of FIGS. 16and 6 in operation,

, depression of the pushbutton 47 will release the ampli-' fying arm 71for movement counterclockwise from its dotted line position to its solidline position'shown in FIG. 6. Upon this occurrence, the amplifying arm71 sweeps across the lever arm 67 causing the shutter plate 61 to rotateclockwise thereby opening or exposing the aperture opening 44. Prior tothis occurrence, in the sequence of events, the additional opening 143in the rotatable plate 69 will have swept across the additional opening144 thereby-allowing light emitted from diode 141 to impinge upon thelight sensitive surface of the LASCR 145. This renders LASCR 145conductive and initiates light emission from a photo lamp (not shown)connected to the terminals 17a, 17b shown'in FIG. 16. This lightemission is timed to occur substantially simultaneously with the maximumopening of the aperture 44 by the shutter plate 61 The extent (diameter)of the optical path provided through the aperture opening 44 iscontrolled by the exposure control 51 in accordance with the ambientlight level as iswell-known inthe art. The time duration of the openingof the aperture 44 will of course be controlled by the time required forthe return spring 65 to return the shutter plate 61 to its normal,quiescent position shown in solid line,in FIG. 6. It will be appreciatedtingdiode 141 to thelightsensitive surface of the LASCR 145 at aparticular point in the angular travel of shutter member 61' where it isdesired to render the LASCR. 145 conductive. By thusmodifyng thearrangement of FIGS.'16 and 6, it nolonger becomes necessary to cut theopenings 143 and 144 in the trigger mechanism shown in FIG. 6. Thissimplifies the manufacture of the assembly, as well as relaxes some ofthe requirements on the location of the LASCR 145 and LED 141.Additionally, because only the formation of a light reflecting surface149 is required, no substantial mass, is

I added to the shutter mechanism 61 thereby enhancing its performance.Further, it might be noted that the provision of the low mass, lightreflective shutter member light emission initiation shown in FIG. 6A,and similar arrangements described herein allows a designer of a camerashutter trigger mechanism to go todirect acting shutter arrangements incontrast to indirect acting shutter trigger mechanisms. This is due tothe fact that the trigger mechanism will now no longer be required toactuate auxiliary electrical contacts or other similar tasks whichimpose a mechanical loading on the trigger mechanism. The result is togreatly simplify the task of 24 of non-use. To avoid this fromhappening, a capacitor 151 is inserted in thecircuit branch between thelight emitting diode 141 and the limiting resistor 142. In thisarrangement, the LASCR 145 again is connected through the photo lamp 17in parallel with the circuit branch including the light emitting diode141 across the, batterysource 15. Here again the photo lamp 17 willserve as an on-off fuse'for discontinuing conduction through the LASCR145 after being flashed, and a new bulb must be inserted in the circuitby the user in order tocondition it for re-use.

Withthe circuit arrangement of FIG. 17, prewinding or cocking of thetrigger mechanism of the camera will automatically open theswitch 16.However, due to the fact that the switch 16 previously was closed'on itsfixed contact, the capacitor 151 will have been charged to the fullvoltageof the battery source 15. Assuming that there is a freshflashbulb 17 in the circuit, then upon closure of switch 16 by the userof the camera, sufficient energy will bedischarged from the capacitor151 through LED 141 to initiate light emission and selectively activatethe light activated SCR 145. This recharacteristic of the LED 141. Itcan be seen that by appropriate design location of the exposure openingsof the camera (not shown) relative to the energization of the LED 141 ata point such as shown by the dotted line, synchronized, contact-lesslight emission initiation can be obtained with the circuit of FIG. 17.Further, because the switching mechanism of the camera is of the typewherein the contacts 16remain closed after use, the inclusion of thecapacitor 151 will prevent further 'current drain on the battery source15 after it has once become charged to the voltage of the battery.

From the foregoing description, it will be appreciated that the presentinventionprovides a family of new and improved'contact-less light'emission initiation circuits for use incontrolling operation of photolamps, flashbulbs, flash cubes, lamp arrays, etc., employed in lightingsubjects to be photographed with a camera. The

' contact-less photo lamp light emission initiation circuits may befabricated in micro-miniaturized integrated circuit form, are capable ofreliable operation even with low voltage electric energy sources, suchas expendable paper batteries, and the like, and may be 4 for cameracontrol systems constructed in accordance with the invention, it isbelieved obvious that'other modifications and variations of the'inventionare possithe designer of the trigger mechanism as well as toallow for improved performance of the mechanism.

FIG. 17 is a schematic circuit diagram of a different form of lightactivated, contact-less light emission initiation circuit for use with acamera control of the type having an on-off switch 16 that is-jnormallyclosed and maintained closed after the taking of a picture.- With suchon-off control switch design, it can be seen that the circuitarrangement-of'FIGS. 15 and 16 would.

ble in the light of the above teachings. It is, therefore, to beunderstood that changes may be made in the particular embodiments of.the invention described which are in the full intended scope of theinvention as deinitiate light emission from the same upon theestablishment of a closed electric current path through the elecacrosssaid electric supply terminal means, means coupling said controlelectrode of the semiconductor 1 synchronization.

switch means to the junction of said device and load resistor, andmagnetic means to impress a magnetic field on said magneticallysensitive semiconductor device in synchronism with the opening of acamera shutter, said magnetically sensitive semiconductor device beingprovided with aplurality of individual magnetically sensitive areas,said magnetic means being adapted to impress said magnetic field on saidmagnetically sensitive areas in time sequence, and including means forselectively connecting any of said magnetically sensitive areas inseries with said load resistor for achieving flash

1. A contact-less photo lamp flashing circuit comprising electric supplyterminal means for connection to a source of electric energy and tophoto lamp means to initiate light emission from the same upon theestablishment of a closed electric current path through the electricsupply terminal means, the source of electric energy and the photo lampmeans to be energized, semiconductor switch means connected in thecurrent path intermediate the photo lamp means and source of electricenergy for controlling the closure of the current path to the photo lampmeans, said semiconductor switch means being provided with a controlelectrode for selectively rendering said semiconductor switch meansconductive, a magnetically sensitive semiconductor device and a loadresistor connected in series across said electric supply terminal means,means coupling said control electrode of the semiconductor switch meansto the junction of said device and load resistor, and magnetic means toimpress a Magnetic field on said magnetically sensitive semiconductordevice in synchronism with the opening of a camera shutter, saidmagnetically sensitive semiconductor device being provided with aplurality of individual magnetically sensitive areas, said magneticmeans being adapted to impress said magnetic field on said magneticallysensitive areas in time sequence, and including means for selectivelyconnecting any of said magnetically sensitive areas in series with saidload resistor for achieving flash synchronization.